// assets/js/lunar.js

// 农历转换工具
const lunarInfo = [
    0x04bd8, 0x04ae0, 0x0a570, 0x054d5, 0x0d260, 0x0d950, 0x16554, 0x056a0, 0x09ad0, 0x055d2,
    0x04ae0, 0x0a5b6, 0x0a4d0, 0x0d250, 0x1d255, 0x0b540, 0x0d6a0, 0x0ada2, 0x095b0, 0x14977,
    0x04970, 0x0a4b0, 0x0b4b5, 0x06a50, 0x06d40, 0x1ab54, 0x02b60, 0x09570, 0x052f2, 0x04970,
    0x06566, 0x0d4a0, 0x0ea50, 0x06e95, 0x05ad0, 0x02b60, 0x186e3, 0x092e0, 0x1c8d7, 0x0c950,
    0x0d4a0, 0x1d8a6, 0x0b550, 0x056a0, 0x1a5b4, 0x025d0, 0x092d0, 0x0d2b2, 0x0a950, 0x0b557,
    0x06ca0, 0x0b550, 0x15355, 0x04da0, 0x0a5d0, 0x14573, 0x052d0, 0x0a9a8, 0x0e950, 0x06aa0,
    0x0aea6, 0x0ab50, 0x04b60, 0x0aae4, 0x0a570, 0x05260, 0x0f263, 0x0d950, 0x05b57, 0x056a0,
    0x096d0, 0x04dd5, 0x04ad0, 0x0a4d0, 0x0d4d4, 0x0d250, 0x0d558, 0x0b540, 0x0b5a0, 0x195a6,
    0x095b0, 0x049b0, 0x0a974, 0x0a4b0, 0x0b27a, 0x06a50, 0x06d40, 0x0af46, 0x0ab60, 0x09570,
    0x04af5, 0x04970, 0x064b0, 0x074a3, 0x0ea50, 0x06b58, 0x055c0, 0x0ab60, 0x096d5, 0x092e0,
    0x0c960, 0x0d954, 0x0d4a0, 0x0da50, 0x07552, 0x056a0, 0x0abb7, 0x025d0, 0x092d0, 0x0cab5,
    0x0a950, 0x0b4a0, 0x0baa4, 0x0ad50, 0x055d9, 0x04ba0, 0x0a5b0, 0x15176, 0x052b0, 0x0a930,
    0x07954, 0x06aa0, 0x0ad50, 0x05b52, 0x04b60, 0x0a6e6, 0x0a4e0, 0x0d260, 0x0ea65, 0x0d530,
    0x05aa0, 0x076a3, 0x096d0, 0x04bd7, 0x04ad0, 0x0a4d0, 0x1d0b6, 0x0d250, 0x0d520, 0x0dd45,
    0x0b5a0, 0x056d0, 0x055b2, 0x049b0, 0x0a577, 0x0a4b0, 0x0aa50, 0x1b255, 0x06d20, 0x0ada0
];

const Gan = ["甲", "乙", "丙", "丁", "戊", "己", "庚", "辛", "壬", "癸"];
const Zhi = ["子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥"];
const Animals = ["鼠", "牛", "虎", "兔", "龙", "蛇", "马", "羊", "猴", "鸡", "狗", "猪"];
const lunarMonths = ["正", "二", "三", "四", "五", "六", "七", "八", "九", "十", "冬", "腊"];
const lunarDays = ["初一", "初二", "初三", "初四", "初五", "初六", "初七", "初八", "初九", "初十",
    "十一", "十二", "十三", "十四", "十五", "十六", "十七", "十八", "十九", "二十",
    "廿一", "廿二", "廿三", "廿四", "廿五", "廿六", "廿七", "廿八", "廿九", "三十"];

// 获取农历年份
function getLunarYear(year) {
    const ganIndex = (year - 4) % 10;
    const zhiIndex = (year - 4) % 12;
    return Gan[ganIndex] + Zhi[zhiIndex] + '年';
}

// 获取农历月份和日期
function getLunarMonthAndDay(date) {
    const year = date.getFullYear();
    const month = date.getMonth();
    const day = date.getDate();

    let i, leap = 0, temp = 0;
    const baseDate = new Date(1900, 0, 31);
    let offset = Math.floor((date - baseDate) / 86400000);

    for (i = 1900; i < 2101 && offset > 0; i++) {
        temp = getLunarYearDays(i);
        offset -= temp;
    }

    if (offset < 0) {
        offset += temp;
        i--;
    }

    const lunarYear = i;
    leap = getLeapMonth(lunarYear);
    let isLeap = false;

    for (i = 1; i < 13 && offset > 0; i++) {
        if (leap > 0 && i === (leap + 1) && !isLeap) {
            --i;
            isLeap = true;
            temp = getLeapMonthDays(lunarYear);
        } else {
            temp = getLunarMonthDays(lunarYear, i);
        }

        if (isLeap && i === (leap + 1)) isLeap = false;

        offset -= temp;
    }

    if (offset === 0 && leap > 0 && i === leap + 1) {
        if (isLeap) {
            isLeap = false;
        } else {
            isLeap = true;
            --i;
        }
    }

    if (offset < 0) {
        offset += temp;
        --i;
    }

    const lunarMonth = i;
    const lunarDay = offset + 1;

    // 获取月份名称
    let monthName = lunarMonths[lunarMonth - 1];
    if (isLeap) monthName = '闰' + monthName;
    monthName += '月';

    // 获取日期名称
    const dayName = lunarDays[lunarDay - 1];

    return { month: monthName, day: dayName };
}

// 获取农历年总天数
function getLunarYearDays(year) {
    let sum = 348;
    for (let i = 0x8000; i > 0x8; i >>= 1) {
        sum += (lunarInfo[year - 1900] & i) ? 1 : 0;
    }
    return sum + getLeapMonthDays(year);
}

// 获取闰月天数
function getLeapMonthDays(year) {
    if (getLeapMonth(year)) {
        return (lunarInfo[year - 1900] & 0x10000) ? 30 : 29;
    }
    return 0;
}

// 获取闰月
function getLeapMonth(year) {
    return lunarInfo[year - 1900] & 0xf;
}

// 获取农历月天数
function getLunarMonthDays(year, month) {
    return (lunarInfo[year - 1900] & (0x10000 >> month)) ? 30 : 29;
}

// 获取完整农历日期
function getFullLunarDate(date) {
    const lunarYear = getLunarYear(date.getFullYear());
    const { month, day } = getLunarMonthAndDay(date);
    return lunarYear + ' ' + month + day;
}

// 导出函数
window.getFullLunarDate = getFullLunarDate;